<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .wrapper{
      width: 500px;
      height: 500px;
      border:  1px solid;
    }
    .box {
      width: 30px;
      height: 30px;
      border-radius: 50%;
      background-color: red;
    }
  </style>
</head>
<body>
  <div class="wrapper">
    <div class="box">

    </div>
  </div>
</body>
</html>